Analytical and design methods for local buckling of pultruded FRP composite structural members

Local buckling is one of the key factors controlling the design of pultruded fiber reinforced polymer (FRP) composite structural members. The research of this work focuses on a typical buckling mode—local buckling. Based on energy method and classic plate theory, an analytical method was developed and proposed for the local buckling of orthotropic pultruded FRP composite beam and column members. In particular, a quadratic polynomial was used as the shape function to simulate the buckling mode, which can satisfy the boundary conditions of the plate elements of pultruded FRP composite profiles. Based on proposed analytical method, a set of semi-empirical design method was constructed for local buckling of pultruded FRP I- and Box-shaped beam and column members. When compared to experimental data, proposed design method shows higher accuracy over current Chinese standard, American standard, European standard, and Kollar method. The proposed analytical and design methods are able to simultaneously consider the local buckling issue of pultruded FRP beam and column members having different cross-sections. In addition, proposed method is capable of being updated in a convenient manner, which well suits the local buckling issue of the thin-walled pultruded FRP composite profiles.